The specific aims of the Phase II research are the development and testing in an animal model of minimally invasive microwave balloon catheter instrumentation for producing biological stents in pancreatic ducts and bile ducts and for producing biological occlusions in blood vessels of the liver. Twelve pigs will be used in the study. The intent will be to dilate the pancreatic ducts to approximately 2-3 mm beyond their native size, to dilate the common bile ducts to larger diameters with and without artificially generated strictures, and to occlude the mesenteric venous and arterial arcades of some of these animals. Gross and histological examinations, as well as liver function tests and imaging will be performed to determine optimum treatment parameters. The temperatures of the treated tissues will be monitored with miniature thermistors that are integrated into the balloons and also with a microwave radiometer. Several of the animals will be maintained in standard animal facility for periods of three and six weeks postoperatively and monitored and tested for any side effects that may have resulted from the procedure. The animal studies are designed to lay the groundwork for follow- on clinical trials of the use of microwave ballooning for dilating pancreatic and biliary strictures and for producing occlusions in blood vessels that supply blood to hepatic tumors. Microwave ballooning of hepatic strictures, if proven to be safe and effective in the proposed animal studies has the potential to lead to better, less complicated, and more durable treatments in the clinical management of such strictures. Similarly, if the animal studies prove that lasting occlusions can be safely produced in hepatic blood vessels;this would have the potential to lead to improved clinical management of hepatic tumors. Since FDA approval is, of course, required before any clinical trials and subsequent commercialization can even begin, part of the program will be devoted to starting the additional animal studies that will be asked for by the FDA, and also to develop prototype instrumentation that will conform to all FDA requirements for use in follow-on clinical trials. The hope is that the microwave balloon catheters and instrumentation developed during the proposed Phase II program will eventually find application not only for producing biological stents in pancreatic ducts and bile ducts and biological occlusions in blood vessels of the liver, but also for dilating strictures in general and for occluding blood vessels that supply blood to a variety of solid malignant tumors. Relevance The microwave balloon catheter instrumentation that would result from the proposed program would enable physicians to safely enlarge the diameters of pancreatic and bile ducts that are narrowed by disease, and to close blood vessels that feed liver cancers. The procedure is minimally invasive, and could be accomplished without having to introduce foreign materials into the body, materials that can sometimes cause serious side effects. PUBLIC HEALTH RELEVANCE: Relevance The instrumentation that would result from the proposed program would enable physicians to safely enlarge the diameters of human canals, ducts and vessels that are narrowed by disease, or to close blood vessels that feed solid cancers. The physician will be able to accomplish this without having to introduce foreign materials into the body, materials that can sometimes cause serious side effects.